The Spanwise Dependence of Vortex-Shedding From Yawed Circular Cylinders

Simultaneous measurements of the fluctuating wall pressure along the cylinder span were used to examine the spanwise characteristics of the vortex-shedding for yaw angles varying from $α=60deg$ to $α=90deg$⁠. The Reynolds number based on the diameter of the cylinder was 56,100. The results indicate that yawing the cylinder to the mean flow direction causes the vortex-shedding in the wake to become more disorderly. This disorder is initiated at the upstream end of the cylinder and results in a rapid decrease in correlation length, from $3.3D$ for $α=90deg$ to $1.1D$ for $α=60deg$⁠. The commonly used independence principle was shown to predict the vortex-shedding frequency reasonably well along the entire cylinder span for $α>70deg$⁠, but did not work as well for $α=60deg$⁠.